This invention relates to a high power transmission arrangement comprising an engageable and disengageable toothed clutch.
Damage may be caused if an attempt is made to engage the toothed clutch whilst the rotary clutch parts thereof are in relative rotation, and it has therefore been usual hitherto to provide speed sensing devices for indicating that the rotary clutch parts are in rotational synchronism and that the toothed clutch is prepared for engagement. The object of the present invention is to avoid the need for such sensing devices.
In our British Patent Specification No. 1,291,773 there is disclosed a pawl and ratchet mechanism which may be operated in both a ratcheting and a pawl free condition in which the pawl and ratchet components of the mechanism are respectively in and out of engagement with each other, the mechanism having a movable baulking member which when in a baulking position prevents relative movement of the said components into the ratcheting condition, the baulking member being maintained in said baulking position when the relative rotation of the said components is inappropriate to permit the mechanism to be operated in the ratcheting condition, and movement imparting means for moving the baulking member out of the baulking position when the said relative rotation is appropriate. The baulking member is provided with stepped baulking teeth which, when the baulking member is in the baulking position, are in effect locked in engagement with blocking teeth on a blocking ring, such locking of the teeth together being desirable to prevent their separation as a result of vibration. When, however, the relative rotation of the pawl and ratchet components is appropriate to permit movement of the baulking member out of the baulking position, there is only a small frictional force between the blocking ring and a bearing therefor which tends to effect such movement of the baulking member out of the baulking position. Consequently it has previously been necessary to constantly try to move the baulking member manually out of the baulking position and this could involve a considerable amount of operator time.